What causes RSD?
The trigger is usually some type of physical injury – anything from a seemingly trivial bump, bruise, or cut to more serious damage from a crushing wound, a stab wound, frostbite, or a burn. Surgery and various forms of disease-including heart attack, stroke, infection, cancer, and spinal arthritis can also start the process.
As the name implies, the condition is believed to start with a reflex arc, with impulses traveling along the nerves from the site of injury to the spinal cord and right back out again. The sympathetic nerves, which arc involved in control of such functions as blood pressure, carry an abnormally high level of impulses back outward.
The result is pain, alterations in blood flow, and dystrophy, or defective growth, referring to the deterioration that will eventually occur in the bones and soft tissues in the affected area. There is no way to predict if or when RSD will develop. Most injuries heal normally but even a minor injury can lead to this condition.
How is RSD, diagnosed?
Most often, RSDS is suspected when pain-usually with a burning sensation-develops several days after an injury, when healing seems to be under way or complete. The most common site is on an upper or lower extremity, but sometimes the condition affects both hands and both feet.
In many cases, the pain is worsened by any kind of touch, including contact with clothing or bed sheets or even a mild breeze against the skin. Movement of the affected limb can also cause intense pain.
There is no specific tests to confirm a diagnosis of RSD. But clinical tests of nerve function, skin tone, and blood flow may provide additional evidence. Scans and x-rays are sometimes used to watch for early damage to bone tissue.
How is RSD treated?
The most common type of treatment is to block the abnormally high levels of impulses flowing out along the sympathetic nerves. Various forms of local anesthesia can be injected in different sites, according to the part of the body affected.
This form of treatment is most effective when the condition is still in the early stages. However, pain relief lasts only as long as the anesthetic keeps working. Thus, the patient requires repeated injections or continuous infusion of these agents.
A very important part of treatment is physical therapy and rehabilitation. Since pain from RSD is often worse with movement, patients tend to try to protect the affected limb by holding it motionless. But lack of motion can lead to muscle deterioration and stiff or “frozen” joints. Physical therapy employs special exercises designed to maintain muscle strength and joint motion. These exercises are crucial to preventing permanent disability. In fact, one of the main goals of nerve blockade is to allow the patient to exercise without intolerable pain.
Is there any drug treatment for RSD?
Certain types of drugs are often used in treating RSD. For example, anti-arthritis drugs may help reduce pain, especially during physical therapy. Antidepressant drugs may also be helpful-and not just because patients with RSD can become depressed about their condition. These drugs also help block the nerve-induced pain that occurs in RSD, and they are just as effective in patients who are not depressed.
Certain drugs routinely used to prevent or stop seizures and others that dilate (open) blood vessels have also shown some promise in treating RSD, but there is less experience with them.
What is the outlook for the patient with RSD?
RSD can be mild or severe. But most often, it is a progressive condition that is, it tends to get worse over time and it rarely goes away by itself. Without treatment, RSD can lead to crippling disability.
Therefore, patients have two responsibilities:
- To seek medical attention for any unexplained onset of burning pain, especially if it develops after an injury
- To cooperate fully with treatment, especially physical therapy
RSD is a serious diagnosis. But although there is no perfect cure, the combination of nerve block or nerve cutting, physical therapy, and drug therapy often provides relief of symptoms and may prevent permanent disability.
